Projected studies of complement biosynthesis in the coming year consist of experiments: 1) To determine the capacity of monocytes from normal and C3 deficient patients to synthesize C3. That is, to determine the specificity of the biochemical defect. 2) To determine the effect of experimental nephrosis in rats on C5 biosynthesis by isolated liver cells in culture. 3) To explore the molecular basis of C4 deficiency in a strain of rats with an x-linked genetic deficiency and to compare this defect to the similar deficiency state in guinea pigs and man. BIBLIOGRAPHIC REFERENCES: Colten, H.R.: Biosynthesis of Complement in Advances in Immunology. Vol. 22, Eds. F.J. Dixon and H. Kunkel, pp. 67-119, Academic Press, N.Y., 1976. Bhan, A.K., Grand, R.J., Colten, H.R., and Alper, C.A.: Liver in gamma 1-antitrypsin deficiency: Morphological observations and in vitro synthesis of gamma 1-antitrypsin. Ped. Res. 10: 35-40, 1976.